Smoking articles

ABSTRACT

THE INVENTION RELATES TO A TOBACCO-SMOKING ARTICLE IN WHICH THE TOBACCO IS CONTAINED IN AN ELONGATED ANNULAR REGION AND AN AXIAL CORE COMPRISING AN ABSORBENT CAPABLE OF SELECTIVELY ABSORBING AROMATIC POLYCYCLIC HYDROCARBONS, FOR EXAMPLE ACTIVATED CHARCOAL OR BASIC ALUMINA, AMMONIUM NITRATE OR OXIDES OF TRANSITION METALS, IS ARRANGED SO THAT THE SMOKE FROM THE COMBUSTION OF THE TOBACCO DRAWN THROUGHT THE SAID CORE BY THE SMOKER.

Oct. 26, 1971 R, E, THORNTON 3,614,956

SMOKING ARTICLES Filed Sept. 5, 1968 #UVEK/70@ RAYA/MMO KE/C mom/radfvrraewffs United States Patent ihce 3,614,956 Patented Oct. 26, 19713,614,956 SMOKING ARTICLES Raymond Eric Thornton, Southampton, England,assiguor to Brown and Williamson Tobacco Corporation, Louisville, Ky.

Filed Sept. 3, 1968, Ser. No. 756,917 Claims priority, applicatio177tBritain, Sept. 7, 1967,

9 Int. Cl. A24d 1/04 U.S. Cl. 131-10.5 10 Claims ABSTRACT F THEDISCLOSURE The invention relates to a tobacco-smoking article in whichthe tobacco is contained in an elongated annular region and an axialcore comprising an absorbent capable of selectively absorbing aromaticpolycyclic hydrocarbons, for example activated charcoal or basicalumina, ammonium nitrate or oxides of transition metals, is arranged sothat the smoke from the combustion of the tobacco is drawn through thesaid core by the smoker.

This invention concerns improvements relating to tobacco smokingarticles, for example of the nature of cigarettes, and has for one ofits objects to provide means for modifying the characteristics oftobacco smoke.

Tobacco smoke consists of a particulate phase which comprises largelythe less volatile constitutents of the smoke in solid or liquid form,and a vapour phase which comprises the more volatile constituents asvapours or gases mixed with the so-called permanent gases.

Various means are available to remove a proportion of the vapour phaseof tobacco smoke, or to remove specific substances therefrom. Forremoving the less volatile particulate phase, use is commonlymade ofmechanical means whereby the aerosol particles are deposited upon abarrier surface. While such means are effective in removing a proportionof the particulate phase, they are ineffective or only partiallyeffective in removing specific substances or groups of substances whichit may be desirable to remove, such as, for example, aromatic polycyclichydrocarbons.

An object of this invention is to provide a smoking article in whichmeans are included to remove a substantial proportion of the aromaticpolycyclic hydrocarbons from the smoke produced on combustion of thetobacco.

According to the invention, a tobacco smoking article comprises tobaccocontained in an elongated annular region and an axial core which is madeof an absorbent capable of selectively absorbing aromatic polycyclichydrocarbons and is arranged so that the smoke from the combustion ofthe tobacco is drawn through the said core. The absorbent core may beformed into a self-sustaining rod or may be totally enclosed in a highlyporous frangible tube. The rod or tube may be wrapped in a layer ofrelatively smoke-impervious paper before being arranged axially of asmoking article of the conventional dimensions of, say, a cigarette. Ifdesired, the smoking article may also be fitted with a filtering orother mouthpiece. Preferably, an impervious barrier of non-combustiblematerial is arranged close to the mouth end of the smoking article toensure that the smoke passes through the axial core and also to arrestthe combustion of the tobacco at a pre-determined point. The absorbentmaterial forming the axial core may comprise a support material, forexample a calcined earth such as one of those available for use in gaschromatography columns under the trade name Celite or Chromosorb, whichincorporates, as by admixture or impregnation, a substantial proportionof a substance which can selectively absorb aromatic polycyclichydrocarbons such as, for instance, activated charcoal or an activatedbasic alumina, ammonium nitrate or oxides of transition metals. Theproportion of the selective absorbent added may be between 5 and 50%calculated on the weight of the support material, but preferably between10 and `40% by weight is applied.

An embodiment of the invention by way of example will now be describedwith reference to the accompanying drawing which is a diagrammatic axialsection through a cigarette.

Tobacco is accommodated in an angular region I1 between an outerwrapping 2 of conventional cigarette paper and an absorbent core 3 fromwhich it is separated by a sleeve of relatively smoke-impervious paper4. Particularly if the core is not self supporting, it may besurrounded, as shown, by a sleeve or tube 5 of very frangible, porous,material, for instance a ceramic material. However, one or other of thesleeves 4 and 5 may be dispensed with. The end of the annular zonetowards the mout-h` piece is closed by an annular member ofsmoke-impervious, non-combustible, material, as illustrated an annulardisc 6 of thin aluminum foil, the opening in the disc being coincidentwith the end of the sleeve or sleeves. The cigarette is terminated by afilter plug 7 filling the whole cross section of the wrapping Such acigarette, without the sleeve 5, can be produced by packing the materialof the core 3, in the form of a stiff paste, into a tube 4 of paper, thefilled tube being then utilised as axial core around which the tobaccois brought to cigarette form within the paper wrapping 2. The disc 6 issecured between the wrapping 2 and the core, using a rubber-basedadhesive.

The filter 7 may be made of a filter paper or of a fibrous material suchas cellulose acetate. If desired, a mouthpiece may be provided beyondthe lter 7, for example and as illustrated by chain lines a flaringmouthpiece 8 made of a plastic material. The end of the core 3 remotefrom the mouthpiece could, if required, be blanked off by a small metaldisc.

In a modification of the cigarette illustrated, the disc '6 is replacedby an annular plug of, for instance, paper impregnated with sodiumsilicate solution and drie-d. A plug of filter material is accommodatedwithin an extension of the sleeve or sleeves 4, 5 into the said annularplug. In this case, the absorbent material may be moulded while moistinto rod form` and wrapped with the filter plug in a paper sleevesimilar to the sleeve 4. A tobacco rod is formed around a hollowcylindrical mandrel of substantially the same diameter as the wrappedcore. The tobacco rod and annular plug are enclosed in the paperwrapping 2. Finally, the core is inserted into the hollow mandrel andthe latter is removed from the tobacco.

Preferably the resistance to air-flow of the core 3` is substantiallygreater than that of the tobacco in the region 1 surrounding it andsuitably about five times greater. Thus a convenient resistance inpractice is 3 cm. water gauge and 20 cm. water gauge respectively forthe tobacco section and the core, both measured at 1050 cc. per minuteair-flow.

With such arrangements, at least a major proportion of the air enteringthe` cigarette will pass initially into the annular region 1 and only aminor proportion into the core 3. Since the end of the annular region 1towards the mouth is closed or substantially closed to the smoke fromthe combustion of the tobacco, this smoke will be constrained, whilestill hot enough to be almost wholly in the vapour phase, to passthrough the axial core, where the aromatic polycyclic hydrocarbons areabsorbed. Hence the general effect of the axial core is that of abuilt-in ilter with the ability to remove aromatic polycyclichydrocarbons selectively.

Several examples employing different core materials will now bedescribed:

EXAMPLE I A tube 4 of conventional cigarette wrapping paper of 3 mm.diameter and 70 mm. length was produced, using a mandrel, as describedwith reference to FIG. 1. Amounts of Celite, a calcined absorptive earthsupplied by the Johns-Manville Products Corporation, and activatedcharcoal both of 30-44 BSS mesh size were mixed in proportions of 90 and10% respectively by weight. The mixture, formed into a stiff paste bythe addition of 20% of glycerol, calculated on the weight of the Celiteemployed, was illed into the tube 4, which was used as the core 3 of acigarette of 8.5 mm. diameter and 70 mm. length prepared from aconventional tobacco blend.

EXAMPLE II The procedure of Example I was repeated, but using, for thecore, Celite of mesh size 30-44 BSS previously sprayed with an aqueoussolution of ammonium nitrate to give, after drying, a 5% increase inweight.

EXAMPLE III The procedure of Example I was repeated, but using, for thecore, Hopcalite, an absorptive mixture consisting largely of the oxidesof transition metals and supplied by Hopkin and Williams Ltd., of meshsize 30-44 BSS.

EXAMPLE IV The procedure of Example I was repeated, but using, for thecore, a mixture of 75% by weight of Celite and 25% by weight of anactivated basic alumina, both of mesh size 30444 BSS.

The cigarettes so produced were attached to iilters, of the paper knownas Myriaj of mm. length and were smoked in comparison with cigarettesprovided with similar lters and containing the same weight of tobacco,but without the axial core. The smoking was performed with a smokingengine which provided one. puff per minute of 2 seconds duration and 35ml. volume. The contents of undesirable aromatic polycyclic hydrocarbonsin the smoke so produced were determined using gas/liquid chromatographytogether with an electron capture detector.

The results obtained were as follows:

Cigarette: Aromatic 1 Control 3.0 Example I 2.4 Example II 2.2 ExampleIII 2.0 Example IV 2.0

1Polycyclic hydrocarbons micrograms/100 cigarettes.

As is evident, an appreciable diminution in the amount of aromaticpolycyclic hydrocarbons in the smoke from the test cigarette can beachieved.

If desired, a small proportion of an alkaline salt, such as sodiumcarbonate, may be added to the core material to effect furthermodification of the smoke. characteristics. The addition is preferablybetween 3 and 8%, for example 5%, calculated on the weight of thesupport material.

I claim:

1. A tobacco smoking article in which the smoke is adapted to befiltered over substantially the entire unsmoked length thereof whichcomprises:

(a) a tubular outer wrapper;

(b) a cylindrical cigarette body having a mouthpiece end and an ignitionend and divided into an annular outer portion made of tobacco smokingmaterial and a central cylindrical core portion made of a tobacco smokelter material other than tobacco with both portions extending forsubstantially the entire length of the cigarette` body;

(c) an annular smoke impervious barrier extending over the end of theannular tobacco smoking material portion at the mouthpiece end of thecigarette; and

(d) a tubular heat destructible smoke impervious barrier positionedbetween the inner surface of the annular tobacco smoking materialportion and the cylindrical ilter material core portion whereby when thetobacco smoking material is ignited at the ignition end and is smokedfrom the mouthpiece end a major portion of the tobacco smoke will bedrawn through the lter material to the mouthpiece end of the cigarettefor the entire unsmoked length of the cigarette.

2. An article as claimed in claim 1, wherein the absorbent core isformed as a self sustaining rod.

3. An article as claimed in claim 1, wherein the absorbent core isenclosed in a porous frangible tube.

4. An article as claimed in claim 1, wherein the core is wrapped in apaper sleeve.

5. An article as claimed in claim 1 and tted with a filteringmouthpiece, communicating with the core, through which the smoke isdrawn.

6. An article as claimed in claim 1, wherein the annular region isclosed towards the mouth end of the article by a barrier ofsmoke-impervious non-combustible material.

7. An article as claimed in claim 1, wherein the core comprises asupport material as well as a substance which can selectively absorbaromatic polycyclic hydrocarbons.

8. An article as claimed in claim 1, wherein the said absorbent isselected from the group consisting of activated charcoal, diatomaceousearth and activated basic alumina.

9. An article as claimed in claim 1, wherein the said absorbent isammonium nitrate.

10. An article as claimed in claim 1, wherein the absorbent comprisesoxides of transition metals.

References Cited UNITED STATES PATENTS 1,616,851 2/1927 Geisler l3l-l0.5UX 2,349,551 5/1944 Helm 13l-10.5 UX 3,217,715 11/1965 Berger et al131-267 X 3,251,365 5/1966 Keith, II et al 131-265 X FOREIGN PATENTS687,136 5/1964 Canada. 1,436,357 3/1966 France. 1,008,092, 10/ 1965Great Britain.

SAMUEL KOREN, Primary Examiner G. M. YAHWAK, Assistant Examiner U.S. Cl.X.R. 131-8, 10.7

